A current paradigm in biomaterials research is the control of protein adsorption on the surface of implantable medical devices. Uncontrolled protein adsorption, leading to a mixed layer of partially denatured proteins, is a hallmark of current biomaterials when implanted. Current surfaces present different cell binding sites from adsorbed plasma proteins such as fibrinogen and immunoglobulin G. Platelets and inflammatory cells such as monocyte/macrophages and neutrophils adhere to these surfaces. When so activated, they secret a wide variety of pro-inflammatory and proliferative factors. These unfavorable events can be controlled by the use of non-fouling surfaces. Non-fouling surfaces are surfaces that absorb little or no protein, primarily due to their hydrophilic surface properties. One prior art approach is to use hyaluronic acid and polyethylene glycol to provide this non-fouling surface characteristic. Biobeneficial coatings are surface coatings that are intended to provide a biological benefit without releasing pharmaceutically active agents. Another type of biobeneficial coating contains free radical scavengers to preserve nitric oxide and prevent oxidative damage.
Langer et al. have published a type of bioabsorbable, polyester polymer that they have dubbed “Biorubber”. (Nature Biotechnology, vol. 20, p. 602, Jun. 2002) This polymer is a polyester copolymer composed of sebacic acid and glycerol. It is a crosslinked elastomer, but possesses no biobeneficial or bioactive moieties. Improved polymers with non-fouling surfaces or with biobeneficial surfaces remain a goal in this art.